This is information on a product in full production.

May 2017

DocID025407 Rev 3

1/19

SRK2000A

Synchronous rectifier smart driver for LLC resonant converters

Datasheet

Features

 Secondary side synchronous rectifier controller

optimized for LLC resonant converters

 Protection against current reversal

 Safe management of load transient, light load

and startup condition

 Matched turn-off thresholds

 Intelligent automatic sleep mode at light load

 Dual gate driver for N-channel MOSFETs with

1 A source and 3.5 A sink drive current

 Operating voltage range 4.5 to 32 V

 Programmable UVLO with hysteresis

 250

µA quiescent consumption

 Operating frequency up to 500 kHz

 Available in SO-8 package

Applications

 All-in-one PC

 High-power AC-DC adapters

 80+/85+ compliant ATX SMPS

 90+/92+ compliant server SMPS

 Industrial SMPS

Description

The SRK2000A smart driver implements a control

scheme specific to secondary side synchronous

rectification in LLC resonant converters that use

a transformer with center tap secondary winding

for full wave rectification.

It provides two high current gate drive outputs,

each capable of driving one or more N-channel

Power MOSFETs. Each gate driver is controlled

separately and an interlocking logic circuit

prevents the two synchronous rectifier MOSFETs

from conducting simultaneously.

The control scheme in this IC allows for each

synchronous rectifier to be switched on as the

corresponding half-winding starts conducting and

switched off as its current goes to zero. The

SRK2000A device implements matched turn-off

MOSFET thresholds. A unique feature of this IC is

its intelligent automatic sleep mode. It allows the

detection of a low-power operating condition for

the converter and puts the IC into a low

consumption sleep mode where gate driving is

stopped and quiescent consumption is reduced.

In this way, converter efficiency improves at light

load, where synchronous rectification is no longer

beneficial. The IC automatically exits sleep mode

and restarts switching as it recognizes that the

load for the converter has increased.

A noticeable feature is the very low external

component count required.

SO-8

Table 1. Device summary

Order code

Package

Packing

SRK2000A

SO-8

Tube

SRK2000ATR

Tape and reel

www.st.com